The present invention relates generally to a headset device for use with the capping machine of the type for applying roll-on closures to a container, and more particularly relates to an improved construction of a headset device which includes a plurality of roll-on mechanisms which are applied under a predetermined, controlled radial force for deforming the closure upon axial displacement of a cone-like cam member.
For many years, capping machines have been in use for applying rool-on closures of the type wherein the skirt of a closure has threads or impressions formed in it by deformation of the skirt against a finish on a container mouth. One kind of roll-on capping machine comprises a rotatable turret and vertically movable capping spindles wherein top pressure is applied against the closures on containers to develop a top seal and/or a side seal, and spinning headsets, including thread rollers on the spindles, move against the closures and rotate around the closures to form threads in the skirts, as described in U.S. Pat. No. 3,303,955. For example, a headset for applying 28 millimeter beverage closures with locking bands (pilferproof ring) preferably includes two each of the thread and band rollers, as described in U.S. Pat. No. 3,760,561.
Heretofore, various types of headset arrangements have been provided for applying closure members operating on the roll-on method. For example, cam operating arrangements have been employed which directly actuate the cam rollers so that there is little or no tolerance for variations in the container dimensions. In addition, improper adjustment of such arrangements may occasionally produce slits in the closure skirt, broken or damaged containers (particularly glass containers) and/or may result in poor thread formation. Recently, a headset device has been employed which utilizes a pneumatic spring arrangement which can be adjusted by regulating the air pressure so as to accommodate the various size containers formed of different materials having different resistance to pressure, as described in U.S. Pat. No. 3,895,478.
Accordingly, in such headset devices the principal problem encountered results from the necessity of having to insure that the roll-on mechanisms acting on the closure perform with the most desirable pressure for the work to be carried out. For example, the radial force employed must be sufficient to form the metal of the roll-on closure to the bottle finish but not excessive enough to cause damage to the closure (shear, swedge, etc.) or bottle finish (spall, fracture, craze, etc.). Insufficient radial force results in a shallow-thread formation. The shallow thread is detrimental principally because (1) objectionably high torques are required by the consumer to twist the shallow-thread closure off the bottle, (2) the pressure containment capability of the shallow-thread closures is inadequate to contain products packaged under pressure, (3) upon a marginally shallow-thread closure subjected to an increase in contained pressure, the closure seals can fail suddenly often blowing the closure from the bottle as an uncontrolled projectile. Accordingly, it is desirable to provide an improved headset which minimizes the problems encountered in prior apparatus and methods for applying roll-on closures.